This invention relates to detecting errors in a memory.
Synchronous data communications networks can carry payload data using, for example, the synchronous digital hierarchy (SDH) protocol or synchronous optical network (SONET) protocol. In each of these protocols, payload data is transported within synchronous payload envelopes (SPE's), in which the payload data is organized into rows. Typically, each row is subdivided into a plurality of data segments, each of which may comprise one or more bytes of data. Lower order signals, which are mapped into columns in the SPE, may be re-arranged one row at a time through a cross-connect device.
In a cross-connect device, it is useful to monitor the data switched through the device to ensure the data is not corrupted. In systems that support a redundant back-up system, detection of corrupted data can be used to trigger a switch-over to a back-up system.